1. Field of the Invention
This invention relates to improvements in an electrophotographic sensitive member having a photoconductive layer formed with amorphous silicon (hereinafter simply referred to as a-Si) produced by glow discharge decomposition or sputtering techniques.
2. Prior Art
Conventionally, materials such as Se, CdS, and SnO are largely used as photosensitive materials for production of an electrophotographic sensitive member. In recent years, however, the application of a-Si to such photosensitive member has been attracting attention, because a-Si has good advantages in respect of resistance to heat and abrasion, freedom from environmental pollution, and photosensitive characteristics.
For example, in a high-density, high-speed recording system known as laser line printer, which utilizes semiconductor laser beams as recording components and which is compact, light in weight and low power consuming, the oscillation wavelength of the semiconductor laser is in the vicinity of 800 nm within the near infrared region, and therefore, researches for an a-Si photosensitive member having high sensitivity to near-infrared radiation have been made. Already, there has been proposed an a-Si layer added with germanium (hereinafter referred to as Ge) in order to increase the photosensitivity sensitivity to near-infrared beams.
However, such Ge-added a-Si photosensitive member has a disadvantage that its charge holding capability is small and further that it allows dark attenuation at a considerably high speed, which fact has limited the practical application thereof. Another difficulty is that the addition of Ge, which is carried out by glow discharge, involves the introduction of GeH.sub.4 gas, which means a considerable increase in production cost because GeH.sub.4 gas is very expensive as compared with SiH.sub.4.